XML 57 R35.htm IDEA: XBRL DOCUMENT
v3.20.4

Summary of Significant Accounting Policies - Rollforward of Unbilled Accounts Receivable (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019
Accounting Policies [Abstract] |  |
Beginning Balance | $ 33,450 | $ 37,227
Recognized during the period | 248,574 | 252,445
Reclassified to receivables | (244,574) | (255,983)
Other | 335 | (239)
Ending Balance | $ 37,785 | $ 33,450

X
- Definition Other unbilled receivables. + References No definition available. + Details
Name: | csgs_OtherUnbilledReceivables
Namespace Prefix: | csgs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Unbilled receivables reclassified to recievables. + References No definition available. + Details
Name: | csgs_UnbilledReceivablesReclassifiedToRecievables
Namespace Prefix: | csgs_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Unbilled receivables recognized during period. + References No definition available. + Details
Name: | csgs_UnbilledReceivablesRecognizedDuringPeriod
Namespace Prefix: | csgs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AccountingPoliciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount received for services rendered and products shipped, but not yet billed, for non-contractual agreements due within one year or the normal operating cycle, if longer. + References No definition available. + Details
Name: | us-gaap_UnbilledReceivablesCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant